[Interactions of Cu2+, Ni2+ and humic acid, bentonite in the water].

Interactions of Cu2+, Ni2+ on humic acid and the mixture adsorbent of humic acid and bentonite were studied. The effects of contact time, initial pH and temperature were determined. The removal rate of the metal ions increased with increasing contact time. The adsorption capacities increased with increasing temperature. Initial pH had a great impact on the removal rate of metal ions, when initial pH was around 7, the maximum removal rate can be achieved. Characteristics of adsorption kinetics of Cu2+, Ni2+ from aqueous solutions on humic acid and mixture adsorbent were studied. The results showed that the adsorption process followed the pseudo second-order equation. The activation energy of Cu2+ on humic acid and mixture adsorbent were 17.01 kJ x mol(-1) and 38.49 kJ x mol(-1), and the activation energy of Ni2+ on humic acid and mixture adsorbent were 15.15 kJ x mol(-1) and 13.35 kJ x mol(-1). The activation energy indicated that the adsorption process belonged to physics adsorption. The adsorption process followed the Langmuir isotherm. deltaH0, deltaS0 and deltaG0 calculated showed that the adsorptions of metal ions on humic acid and mixture adsorbent were endothermic, entropy increasing and spontaneous.